This invention relates to a vacuum suction device, in particular a vacuum lifter, intended for temporary fixing on a substantially smooth, air-impermeable fixing area and comprising a supporting cup and a flexible suction plate as well as an actuating mechanism for creating a partial vacuum between the suction plate and the fixing area while dislocating the suction plate at least in some regions, with an indication device for indicating the partial vacuum being provided and having an indicating element that is mechanically coupled to the suction plate.
In a vacuum suction device, the indication of the partial vacuum is frequently desired with regard to the operation safety of the vacuum suction device to thus prevent that the vacuum suction device is loaded even though the partial vacuum falls below the minimum partial vacuum and that the vacuum suction device unexpectedly detaches from the fixing area. This may apply to the use of the vacuum suction device for lifting objects, in order to avoid damage to the object that includes the fixing area, or to the employment of the vacuum suction device as a handle that is temporarily fixed on a fixing area and used by individuals for instance as an additional grip handle allowing the individual to move more safely in certain surroundings, e.g. in sanitary areas. It is important in this case to be able to check if the partial vacuum is sufficient for guaranteeing personal safety under the loads to be expected.
Vacuum suction devices having means for indicating the partial vacuum are known. In such devices, the partial vacuum is measured directly in the vacuum chamber formed between the suction plate and the fixing area and is indicated by means of an electronic indication device or manometer indication. The determination of the vacuum by applying measuring techniques is comparatively complex in these devices. Further, the indication is based on indication devices in which the indicated parameters are frequently difficult to read and which are operated by technically non-trained personnel. It is not always easy for such individuals to realize on the indication device that a predetermined partial vacuum has decreased below the limit. Further, if the vacuum suction device is used in the sanitary area, for instance to make it easier for an individual to move in a bathroom, swimming pool or the like, it must be taken into account that the indication device is often subject to splash water, condensate etc. and cannot be read for this reason. On the other hand, an electronic device requires complicated encapsulation or does not work correctly. On the other side, such vacuum suction devices can partly be employed also in surroundings with an increased dirt and dust exposure, in which case a manometer indication device is susceptible to malfunction. Safe operation of the indication device is thus not possible under such conditions.
A mechanical design of an indication device of a vacuum lifter is known from German utility model DE 20 2007 008 376 U1. But this indication device is integrated in the suction plate, so that its manufacture is complicated. Further, special designs of the suction plate are required if a vacuum lifter having an indication device is to be provided instead of a vacuum lifter without an indication device. This requires additional stock-keeping, if necessary of the entire assembly consisting of handle and suction plate, and is an obstacle to modular construction. Further, it is difficult for untrained individuals to find the indication device, because it is integrated and hidden in the suction plate.